Computing devices can perform various functions, such as executing applications, receiving user input, and outputting information for display. For instance, computing devices may execute applications, such as an email client, travel assistant, messaging client, and the like. In order to maintain state information across devices (e.g., user preferences, user interest information, historical user behavior information, etc.), the user typically is required to create user account for the application or otherwise provide personally identifiable information so that servers associated with the application may store the state information such that, when the user logs in at the different device or after an application reinstall, the servers may identify the user and send the state information for the user to the device.